Both sides are feature free so let's look straight at the back. Considering the size of the case, connectivity is surprisingly impressive. Six more USB ports and two PS2 ports give as much peripheral connectivity as you could possibly require and having both DVI and VGA video outputs provides plenty of flexibility in monitor choice. Businesses with older equipment may be sorry to see the lack of a parallel or serial port but considering the length of time these connections have been superseded, it's hardly a surprising move. A 10/100/1000 Ethernet port takes care of network duties and a pair of line-in and line-out jacks look after audio. What you won't find, though, is a standard three pin power socket and that's because the dc7800p uses an external power brick which connects via the tiny coaxial socket on the left.
Internally, things are much as you would expect and there's little room for maneuver. And, although this is to be expected we have seen better layouts with the likes of the NEC PowerMate ML460 Pro in particular springing to mind. That sports a fold out hard drive and CD drive mounts, which makes maintenance very easy. That said it uses a larger chassis and the same may not be achievable within the confines of the dc7800p.
Also as a result of its particularly small internals, HP's latest ultra slim has dropped the expansion card slot that was present on the dc7700 series. While this may seem like a step backwards it is worth reiterating that the dc7800p is markedly smaller than its outgoing cousin so compromises had to be made somewhere. However, we're not sure whether the extra space saved on the new chassis is really so important to most people when compared to the greater flexibility provided by the possibility of expansion. Ultimately it comes down on how you plan to use the systems.
Bar the CPU, all the internal components are of the laptop variety with SO-DIMMs used for RAM, the aforementioned slim CD drive, and a 2.5inch hard drive all in use. Inevitably this affects performance with the slow laptop drive in particular feeling sluggish. The big problem, though, was the onboard graphics that actually struggled to power the Aero graphics of Vista. This should be of little concern to most potential users of the dc7800 as turning Aero off soon makes the system nice and snappy but if your software uses anything more sophisticated than the most basic of 2D interfaces then you may find things slow down again. At least the dual-core CPU keeps everyday productivity ticking over nicely.
With the Compaq dc7800p Ultra Slim Desktop, HP has created a compelling solution for large businesses requiring a small, low-power fully featured PC. If all that's required is power enough to run productivity programs or a corporate database then this has to be a good bet. If you require anything more, though, you may have to opt for something larger with a bit more grunt.